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P A R T 6
Drugs acting on the endocrine system
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The mineralocorticoids stimulate retention of
sodium and water and excretion of potassium. These
drugs are used therapeutically in conjunction with
glucocorticoids to treat adrenal insufficiency.
KEY POINTS
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Individuals receiving mineralocorticoids need to
be evaluated for possible hypokalaemia and its
associated cardiac effects and for fluid retention that
could exacerbate heart failure and cause electrolyte
abnormalities.
CHAPTER SUMMARY
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The adrenal medulla is basically a sympathetic nerve
ganglion that releases noradrenaline and adrenaline
into the bloodstream in response to sympathetic
stimulation.
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The adrenal cortex produces three types of
corticosteroids: androgens (male and female sex
hormones), glucocorticoids and mineralocorticoids.
■■
The corticosteroids are released normally in a
diurnal rhythm, with the hypothalamus producing
peak levels of corticotropin-releasing hormone
(CRH) around midnight; peak adrenal response
occurs around 9 a.m. The steroid levels drop slowly
during the day to reach low levels in the evening,
when the hypothalamus begins CRH secretion,
with peak levels again occurring around midnight.
Corticosteroids are also released as part of the
sympathetic stress reaction to help the body conserve
energy for the fight-or-flight response.
■■
Prolonged use of corticosteroids suppresses the
normal hypothalamic–pituitary axis and leads
to adrenal atrophy from lack of stimulation.
Corticosteroids need to be tapered slowly after
prolonged use to allow the adrenals to resume steroid
production.
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The glucocorticoids increase glucose production,
stimulate fat deposition and protein breakdown and
inhibit protein formation. They are used clinically to
block inflammation and the immune response and in
conjunction with mineralocorticoids to treat adrenal
insufficiency.
■■
The mineralocorticoids stimulate retention of sodium
and water and excretion of potassium. They are used
therapeutically in conjunction with glucocorticoids to
treat adrenal insufficiency.
■■
Adverse effects of corticosteroids are related to
exaggeration of the physiological effects; they include
immunosuppression, peptic ulcer formation, fluid
retention and oedema.
■■
Corticosteroids are used topically and locally to
achieve the desired anti-inflammatory effects at a
particular site without the systemic adverse effects
that limit the usefulness of these drugs.
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Care considerations for
people receiving mineralocorticoids
Assessment: History and examination
■
■
Assess for allergy to these drugs
to avoid
hypersensitivity reactions
; history of heart failure,
hypertension or infections; high sodium intake;
breastfeeding; and pregnancy,
which could be
cautions or contraindications to use of the drug
.
■
■
Assess blood pressure, pulse and adventitious
breath sounds; weight and temperature; tissue
turgor; reflexes and bilateral grip strength; and
serum electrolyte levels,
to determine baseline
status before beginning therapy and for any
potential adverse effects
.
Implementation with rationale
■
■
Use only in conjunction with appropriate
glucocorticoids
to maintain control of electrolyte
balance.
■
■
Increase dose in times of stress
to prevent adrenal
insufficiency and to meet increased demands for
corticosteroids under stress.
■
■
Monitor for hypokalaemia (weakness, serum
electrolytes)
to detect the loss early and treat
appropriately.
■
■
Discontinue if signs of overdose (excessive weight
gain, oedema, hypertension, cardiomegaly)
occur
to prevent the development of more severe
toxicity.
■
■
Provide thorough teaching, including drug name,
dosage and administration; measures to avoid
adverse effects; warning signs of problems; and the
need for regular evaluation, including blood tests,
to enhance knowledge about drug therapy and
promote compliance.
Evaluation
■
■
Monitor response to the drug (maintenance of
electrolyte balance).
■
■
Monitor for adverse effects (fluid retention,
oedema, hypokalaemia, headache).
■
■
Evaluate the effectiveness of the teaching plan
(person can name drug, dosage, adverse effects to
watch for and specific measures to avoid them).
■
■
Monitor effectiveness of comfort measures and
compliance with the regimen.
